export class Left<L, A> {
    readonly value: L
  
    constructor (value: L) {
    	this.value = value
    }
  
    isLeft (): this is Left<L, A> {
    	return true
    }
  
    isRight (): this is Right<L, A> {
    	return false
    }
}
  
export class Right<L, A> {
    readonly value: A
  
    constructor (value: A) {
    	this.value = value
    }
  
    isLeft (): this is Left<L, A> {
    	return false
    }
  
    isRight (): this is Right<L, A> {
    	return true
    }
}
  
export type Either<L, A> = Left<L, A> | Right<L, A>
  
export const left = <L, A>(l: L): Either<L, A> => {
	return new Left<L, A>(l)
}
  
export const right = <L, A>(a: A): Either<L, A> => {
	return new Right<L, A>(a)
}